<template>
  <div class="course">
    <Header></Header>
    <div class="main">
      <!-- 筛选条件 -->
      <div class="condition">
        <ul class="cate-list">
          <li class="title">课程分类:</li>
          <li :class="category===0?'this':''" @click="category=0">全部</li>
          <li :class="category===item.id?'this':''" v-for="item in category_list" @click="category=item.id">{{item.name}}</li>
        </ul>
        <div class="ordering">
          <ul>
            <li class="title">筛&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;选: </li>
            <li class="default" :class="change_cls('id',orders)" @click="change_orders('id')">默认</li>
            <li class="hot" :class="change_cls('students',orders)" @click="change_orders('students')">人气</li>
            <li class="price" :class="change_cls('price',orders)" @click="change_orders('price')">价格</li>
          </ul>
          <p class="condition-result">共21个课程</p>
        </div>

      </div>
      <!-- 课程列表 -->
      <div class="course-list">
        <div class="course-item" v-for="course in course_list">
          <div class="course-image">
            <img :src="course.course_img" :alt="course.name">
          </div>
          <div class="course-info">
            <h3><router-link :to="`/course/${course.id}?num=100`">{{course.name}}</router-link> <span><img src="/static/image/avatar1.svg" alt="">{{course.students}}人已加入学习</span></h3>
<!--            <h3><router-link :to="path:`/course/${course.id}?num=100`, query:{num:100}">{{course.name}}</router-link> <span><img src="/static/image/avatar1.svg" alt="">{{course.students}}人已加入学习</span></h3>-->
            <p class="teather-info">{{course.teacher.name}} {{course.teacher.signature}} {{course.teacher.title}} <span>共{{course.lessons}}课时/{{course.pub_lessons===course.lessons?'更新完成':`已更新${course.pub_lessons}个课时`}}</span></p>
            <ul class="lesson-list">
              <li v-for="lesson, key in course.lesson_list">
                <router-link :to="lesson.section_link">
                  <span class="lesson-title">0{{key+1}} | 第{{lesson.lesson}}节：{{lesson.name}}</span>
                  <span class="free" v-if="lesson.free_trail">免费</span>
                </router-link>
              </li>
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：{{course.price}}元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
        <el-pagination
          @size-change="handleSizeChange"
          @current-change="handleCurrentChange"
          background
          layout="sizes, prev, pager, next, jumper, total"
          :page-sizes="[2, 5, 10, 20]"
          :page-size="size"
          :total="course_count">
        </el-pagination>
      </div>
    </div>
    <Footer></Footer>
  </div>
</template>

<script>
  import Header from "./common/Header"
  import Footer from "./common/Footer"
  export default {
      name: "Course",
      data(){
        return{
          category:0,
          course_count: 0,
          category_list: [],
          course_list:[{
              teacher:{},
          }],
          orders: "id", // id表示默认正序,-id表示默认倒序，students表示人气正序，...,price表示价格...
          size: 2,  // 每页显示的数据量
          page: 1,  // 默认当前页码
        }
      },
      components:{
        Header,
        Footer,
      },
      watch:{
        category(){
          // 在切换不同分类时，重新组装ajax请求参数，获取课程列表
          this.page = 1;
          this.get_course();
        },
        orders(){
          // 在切换不同的排序方式时，重新组装ajax请求参数，获取课程列表
          this.get_course();
        },
        size(){
          // 在切换不同页面数据量显示数据量大小的时候
          this.page = 1;
          this.get_course();
        },
        page(){
          // 在切换不同页码的时候
          this.get_course();
        },
      },
      mounted() {
          this.get_course_category();
          this.get_course();
      },
      methods:{
          get_course_category(){
              // 获取课程分类列表
              this.$axios.get(`${this.$settings.Host}/course/category/`).then(response=>{
                 this.category_list = response.data;
              }).catch(error=>{
                 this.$alert("网络错误！获取课程分类信息失败！","路飞学城");
              });
          },
          change_orders(type){
              // 修改排序方式
              if(this.orders===type){
                this.orders = "-"+type;
              }else {
                  this.orders = type;
              }
          },
          change_cls(type,orders){
              if(type==="id" && orders === "id"){
                  return "this asc";
              }else if(type === "id" && orders === "-id"){
                  return "this desc";
              }else if(type === "students" && orders === "students"){
                  return "this asc";
              }else if(type==="students" && orders === "-students"){
                  return "this desc";
              }else if(type==="price" && orders === "price"){
                  return "this asc";
              }else if(type==="price" && orders === "-price"){
                  return "this desc";
              }
          },
          get_course(){
              // 获取课程列表
              let filter = {
                ordering: this.orders,
                size: this.size,
                page: this.page,
              };
              if(this.category > 0){
                filter.course_category = this.category;
              }
              this.$axios.get(`${this.$settings.Host}/course/`,{
                params:filter,
              }).then(response=>{
                  this.course_list = response.data.results;
                  this.course_count = response.data.count;
              }).catch(error=>{
                  this.$alert("网络错误！获取课程信息失败！","路飞学城");
              });
          },
          handleSizeChange(size){
            // 分页组件页面页面数据量大小发生改变时、
            this.size = size;
          },
          handleCurrentChange(page){
            // 分页组件页码发生改变时
            this.page = page;
          },
      }
  }
</script>



<style scoped>
  .course{
    background: #f6f6f6;
  }
  .course .main{
    width: 1100px;
    margin: 35px auto 0;
  }
  .course .condition{
    margin-bottom: 35px;
    padding: 25px 30px 25px 20px;
    background: #fff;
    border-radius: 4px;
    box-shadow: 0 2px 4px 0 #f0f0f0;
  }
  .course .cate-list{
    border-bottom: 1px solid #333;
    border-bottom-color: rgba(51,51,51,.05);
    padding-bottom: 18px;
    margin-bottom: 17px;
  }
  .course .cate-list::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .cate-list li{
    float: left;
    font-size: 16px;
    padding: 6px 15px;
    line-height: 16px;
    margin-left: 14px;
    position: relative;
    transition: all .3s ease;
    cursor: pointer;
    color: #4a4a4a;
    border: 1px solid transparent; /* transparent 透明 */
  }
  .course .cate-list .title{
    color: #888;
    margin-left: 0;
    letter-spacing: .36px;
    padding: 0;
    line-height: 28px;
  }
  .course .cate-list .this{
    color: #ffc210;
    border: 1px solid #ffc210!important;
    border-radius: 30px;
  }
  .course .ordering::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .ordering ul{
    float: left;
  }
  .course .ordering ul::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .ordering .condition-result{
    float: right;
    font-size: 14px;
    color: #9b9b9b;
    line-height: 28px;
  }
  .course .ordering ul li{
    float: left;
    padding: 6px 15px;
    line-height: 16px;
    margin-left: 14px;
    position: relative;
    transition: all .3s ease;
    cursor: pointer;
    color: #4a4a4a;
  }
  .course .ordering .title{
    font-size: 16px;
    color: #888;
    letter-spacing: .36px;
    margin-left: 0;
    padding:0;
    line-height: 28px;
  }
  .course .ordering .this{
    color: #ffc210;
    position: relative;
  }
  .course .ordering .this::before,
  .course .ordering .this::after{
    cursor: pointer;
    content:"";
    display: block;
    width: 0px;
    height: 0px;
    border: 5px solid transparent;
    position: absolute;
    right: 0;
  }
  .course .ordering .this::before{
    border-bottom: 5px solid #aaa;
    margin-bottom: 2px;
    top: 2px;
  }
  .course .ordering .this::after{
    border-top: 5px solid #aaa;
    bottom: 2px;
  }
  .course .ordering .asc::before{
    border-bottom: 5px solid #ffc210;
  }
  .course .ordering .desc::after{
    border-top: 5px solid #ffc210;
  }
  .course .course-item:hover{
    box-shadow: 4px 6px 16px rgba(0,0,0,.5);
  }
  .course .course-item{
    width: 1050px;
    background: #fff;
    padding: 20px 30px 20px 20px;
    margin-bottom: 35px;
    border-radius: 2px;
    cursor: pointer;
    box-shadow: 2px 3px 16px rgba(0,0,0,.1);
    /* css3.0 过渡动画 hover 事件操作 */
    transition: all .2s ease;
  }
  .course .course-item::after{
    content:"";
    display: block;
    clear: both;
  }
  /* 顶级元素 父级元素  当前元素{} */
  .course .course-item .course-image{
    float: left;
    width: 423px;
    height: 210px;
    margin-right: 30px;
  }
  .course .course-item .course-image img{
    width: 100%;
  }
  .course .course-item .course-info{
    float: left;
    width: 596px;
  }
  .course-item .course-info h3 {
    font-size: 26px;
    color: #333;
    font-weight: normal;
    margin-bottom: 8px;
  }
  .course-item .course-info h3 span{
    font-size: 14px;
    color: #9b9b9b;
    float: right;
    margin-top: 14px;
  }
  .course-item .course-info h3 span img{
      width: 11px;
      height: auto;
      margin-right: 7px;
  }
  .course-item .course-info .teather-info{
      font-size: 14px;
      color: #9b9b9b;
      margin-bottom: 14px;
      padding-bottom: 14px;
      border-bottom: 1px solid #333;
      border-bottom-color: rgba(51,51,51,.05);
  }
  .course-item .course-info .teather-info span{
      float: right;
  }
  .course-item .lesson-list::after{
      content:"";
      display: block;
      clear: both;
  }
  .course-item .lesson-list li {
    float: left;
    width: 44%;
    font-size: 14px;
    color: #666;
    padding-left: 22px;
    /* background: url("路径") 是否平铺 x轴位置 y轴位置 */
    background: url("/static/image/play-icon-gray.svg") no-repeat left 4px;
    margin-bottom: 15px;
  }
  .course-item .lesson-list li .lesson-title{
      /* 以下3句，文本内容过多，会自动隐藏，并显示省略符号 */
      text-overflow: ellipsis;
      overflow: hidden;
      white-space: nowrap;
      display:inline-block;
      max-width: 200px;
  }
  .course-item .lesson-list li:hover{
      background-image: url("/static/image/play-icon-yellow.svg");
      color: #ffc210;
  }
  .course-item .lesson-list li .free{
      width: 34px;
      height: 20px;
      color: #fd7b4d;
      vertical-align: super;
      margin-left: 10px;
      border: 1px solid #fd7b4d;
      border-radius: 2px;
      text-align: center;
      font-size: 13px;
      white-space: nowrap;
  }
  .course-item .lesson-list li:hover .free{
      color: #ffc210;
      border-color: #ffc210;
  }
  .course-item .pay-box::after{
    content:"";
    display: block;
    clear: both;
  }
  .course-item .pay-box .discount-type{
    padding: 6px 10px;
    font-size: 16px;
    color: #fff;
    text-align: center;
    margin-right: 8px;
    background: #fa6240;
    border: 1px solid #fa6240;
    border-radius: 10px 0 10px 0;
    float: left;
  }
  .course-item .pay-box .discount-price{
    font-size: 24px;
    color: #fa6240;
    float: left;
  }
  .course-item .pay-box .original-price{
    text-decoration: line-through;
    font-size: 14px;
    color: #9b9b9b;
    margin-left: 10px;
    float: left;
    margin-top: 10px;
  }
  .course-item .pay-box .buy-now{
    width: 120px;
    height: 38px;
    background: transparent;
    color: #fa6240;
    font-size: 16px;
    border: 1px solid #fd7b4d;
    border-radius: 3px;
    transition: all .2s ease-in-out;
    float: right;
    text-align: center;
    line-height: 38px;
  }
  .course-item .pay-box .buy-now:hover{
    color: #fff;
    background: #ffc210;
    border: 1px solid #ffc210;
  }
  .el-pagination{
    text-align: center;
    margin: 15px 0 25px;
  }
</style>
